With its god of thunder "Thor" lighting up the box office this weekend, Marvel has struck again at the multiplex.

The 3-D sequel "Thor: The Dark World" debuted with a healthy $86 million, according to an estimate from Marvel distributor Walt Disney Studios. That's the fourth-highest opening of the year, but well behind another Marvel property, "Iron Man 3," whose $174-million debut is still the biggest of 2013.

Heading into the weekend, prerelease audience surveys suggested the comic book adaptation would debut with a minimum of $90 million -- and given strong early interest, even a $100-million launch didn't appear impossible. Of course, $86 million is still a great start -- significantly more than the $65.7 million the original "Thor" launched with in 2011. And although "The Dark World" cost Marvel Entertainment $170 million to produce, the film is likely going to do so well overseas that the studio will end up in good shape.

And yet a film from the Marvel universe is held to exceptionally high standards. The first "Thor," which in the end collected $181 million domestically and $268 million abroad, wasn't viewed as a massive hit -- but it was the first film in a franchise, so it was given the benefit of the doubt. Now that the sequel has launched, it seems clear that the "Thor" movies are not destined to perform at the rate that the "Iron Man" films do.

This summer, audiences went crazy for Robert Downey Jr. in "Iron Man 3" as the film raked in an insane $1.2 billion worldwide. The movie no doubt benefited from the success of "The Avengers," which in summer 2012 became the top-grossing film of the year with $1.5 billion in global sales. "The Avengers" features both Iron Man and Thor, along with other Marvel superheroes such as the Hulk and Captain America. (An "Avengers" sequel is planned for release in 2015.)

Because the latest "Thor" release is hitting theaters in the wake of "The Avengers" and May's "Iron Man 3," some expected "The Dark World" to see an even larger bump at the box office. But holding "Thor" up against Marvel's other brands isn't fair, says Dave Hollis, Disney's executive vice president of distribution.

“Jumping to comparisons with ‘Iron Man’ or ‘The Avengers’ is not terribly appropriate. Any time you can wake up to a $80-million-plus opening, you’re appreciative,” Hollis said. “Yes, there are certain stories in the Marvel universe that have lent themselves to being the broadest, but there are others that can still put up extraordinary numbers.”

"The Dark World" stars 30-year-old Chris Hemsworth as Thor, the god of thunder who teams up with his deceitful brother Loki (Tom Hiddleston) to defeat an evil foe. Although the movie earned somewhat less favorable reviews than the original "Thor" -- 66% vs. 77% "fresh" ratings on Rotten Tomatoes -- audiences responded better to the sequel. Those who saw the new movie this weekend assigned it an average grade of A-, according to market research firm CinemaScore; the original "Thor" earned a B+.

As expected, “The Dark World” appealed to a more male audience this weekend; just 38% of the crowd was female. Disney also reported that most moviegoers -- about 51% -- were between the ages of 18 and 34.

Heading into the weekend, “The Dark World” had already grossed well over $100 million abroad. Playing in 66 foreign markets this weekend, the film raked in an additional $94 million, bringing its international total to $240.9 million. The first “Thor” made $268 million overseas all told, so the sequel is on pace to far exceed that tally.

The movie is performing best in Russia, where it has collected $24.1 million, but it has also made around $20 million in Britain and China. In the latter, the movie opened to $19.6 million -- in one weekend surpassing the total gross the original made in China in 2011.

Back in the U.S., no other brand-new film dared to face off against "Thor." The romantic drama "About Time," which played in limited release last weekend, expanded to 1,200 theaters and grossed an underwhelming $5.2 million. The Universal Pictures film about a young man (Domhnall Gleeson) who is blessed with the ability to time travel has now grossed $6.7 million in North America -- far less than the $38.2 million it's made abroad. The movie has performed best in Britain, where the film is set and where its writer-director Richard Curtis hails from.

"12 Years a Slave," which has each weekend been slowly adding theaters since its debut in mid-October, finally reached a wide audience in 1,144 locations this weekend. Fox Searchlight's critical darling did a bit better than "About Time," grossing $6.6 million and raising its overall tally to a respectable $17.3 million.